Convection heater



July 15, 1958 T. K. HINE CONVECTION HEATER Filed Sept. 16, 1955INVENTOR. 7 76176} #2713 Unite States Patent coisvirc'rioN HEATERTredick K. Hine, Huntington Woods, Mich., assignor to ChryslerCorporation, Highland Park, Mich., a corporation of Delaware ApplicationSeptember 16, 1955, Serial No. 534,674

4- Claims. (Cl. 257136) This invention relates to improvements inconvection heaters of the type employed for space heating.

Convection heaters of the aforesaid type are conventionally installed inrooms of oifice buildings, hotels, dwellings, and the like. In suchinstallations the heating element is usually located in an enclosureopen at the region of the floor to provide an air inlet and at the topto provide an outlet for the heated air. This enclosure is intended toprovide an upright warm air stack or duct and is conventionally locatedadjacent an outside wall of the room and below a window.

Convection heaters conventionally installed as aforesaid have, prior tomy invention, an inherent and most objectionable action in that theyinduce a flow of cold air currents in the rooms being heated. This givesrise to objectionable drafts of cold air which are not only disturbingto the occupants but sometimes induce colds and other disorders. Theseobjectionable cold air drafts are of an intensity in proportion to thedrop in ambient temperature which increases the discomfort of theoccupants as the weather becomes colder.

It is an object of my invention to provide a convection heater of theaforesaid type adapted for installation as aforesaid but which willovercome the aforesaid objections.

Another object is to provide a convection heater of simple constructionand of very low cost in relation to conventional heaters of this generaltype which, when installed adjacent and below a window, will operateefficiently in heatingthe room to the desired temperature withoutaccompanying cold air drafts.

A further object is to provide a simple means capable of attachment tomany commercial types of convection heaters whereby they may be readilyand quickly converted at low cost so as to attain the aforesaid objectsof my invention.

In carrying out my invention 1 provide, in instances of conventionalnormal depth sills, a convenient form of baffle projection from theinner rear wall of the upright warm air stack toward the inner frontwall thereof and disposed between the heating element and the stackoutlet. This baflie terminates short of the inner front wall so as todeflect the current of cold air falling downwardly adjacent the windowglass and divert it upwardly into a stream of warm air by merging withthe warm air currents passing toward and from the outlet of theconvection heater. The baffle further produces a jet or venturi-likeaction on the warm air in that in rising to the restriction provided bythe space between the baffle and the inner front wall of the stack, thevelocity of the warm air is accelerated and thus effectively diverts thefalling cold air and causes it to flow upwardly with the warm air. As aresult there are no cold air downdrafts, as heretofore, either throughthe stack or adjacent thereto and the room occupants are not aware ofany flow of air currents.

In instances of relatively wide sills which are sometimes experienced,my invention contemplates location of the aforesaid baffle projectionfrom the inner front wall of the upright warm air stack toward the innerrear wall thereof and disposed, as aforesaid, between the heatingelement and the stack outlet. This bafl'le terminates short of the innerrear wall so as to deflect the aforesaid current of cold falling air anddivert it upwardly into a stream of warm air as aforesaid. Sucharrangement produces the aforesaid venturi-like action by accelerationof the rising warm air with the same beneficial results but with thisdifference, that is, in this instance the falling cold air is deflectedupwardly largely at the zone of the wide sill area.

Further objects and advantages of my invention will be apparent from thefollowing detailed illustration of several embodiments thereof,reference being had to the accompanying drawing in which:

Figure 1 is a front elevational View of my convection heater illustratedin operative position adjacent and below a window;

Figure 2 is a sectional elevation view -2 of Figure 1;

Figure 3 is a diagrammatic view illustrating typical air current flowfor my convection heater;

Figure 4 is a similar view illustrating typical air current flow for aconventional convection heater; and

Figure 5 is a view generally similar to Figure 2 but illustrating myconvection heater applied to a relatively wide sill adjacent a window.

In the drawings the convection heater A is shown installed adjacent andbelow the window B of the outside wall B of the typical room C. Thisheater is provided with an upright warm stack or duct lit having thesheet metal opposed front and rear wall portions 11 and 12 respectively,opposed upright end walls 12', and the bottom boundary 13 which, in thisinstance, is the room floor. At its upper end the duct is provided withan outlet grille 14 for the warm air and, for the sake of appearance, ispreferably flush with the window sill 15' which, in this instance, is ofnormal relatively narrow depth. For the same reason of appearance theduct is provided with a finish enclosure 16 which terminates short ofthe floor 13 to provide an air inlet 17 to the heating element 18mounted adjacent the inlet and across the lower end of the sheet metalduct 12 so that the air entering the inlet 17 passes through the heatingelement.

The heating element 18 may be of any well known type such as hot water,electrical, or steam. Extending from the inner face of the rear wall 11of duct it) and fixedly secured thereto is a battle D of heat resistantmaterial such as ordinary tin or other metallic sheeting which extendslongitudinally within and preferably the length of the duct. This bafileD provides a restricted warm air orifice 19 preferably closer to theoutlet grille 14 than to the heating element 18. Although the baffle Dmay be of any shape, such as a planar sheet metal element extendingperpendicular to the rear wall 11, I preferably provide an inclinedbaffie, which in addition may be concaved downwardly as illustrated, inorder to minimize eddy currents in the upward flow of warm air and thusincrease the elliciency of the air flow. I have obtained good resultswith the bafile arranged generally as illustrated, that is, such thatthe orifice 19 is roughly onequarter to one-fifth of the distance fromthe grille 14 to the heating element 18. The baffle D divides the duct10 into zones or portions as follows.

The duct portion 20 below baffle D comprises a warm air riser leadingupwardly from the heating element 18 to the orifice portion 19 betweenthe baffle and wall 12. Above the bafile is a duct portion 21 adjacentthe bottom of window B while above the orifice 19 there is a portion 22of warm air of accelerated velocity relative to that of the warm airbelow the bafile.

taken along line With the heater A arranged generally as illustrated inrelation to the window B, the naturally induced cold downdraft of air,indicated by solid arrow lines 23, enters the grille 14 into ductportion 21 and is caused to reverse its flow as it is deflected by thehigh velocity warm air, indicated by dotted arrow lines 24, rising fromduct portion 20 and orifice portion 19 whence it is entrained in region22 with the cold air. Thus the cold air is isolated or shielded from theroom by a curtain of warm air rising from orifice 19 throughout thelength of the heater A and window B. The falling cold air is preventedfrom passing from the window to the room and is caused to flow into theduct portion 21 for entrainment with the warm air discharged throughorifice 19. The cold air is thus mixed with the warm air and both travelupwardly to the ceiling and thence generally as indicated in Figure 3 ina looping path for the length of the room and back along the floor tothe inlet 17. It will-be noted that the cold air, although naturallyinduced in downward currents along the window, cannot escape downwardlythrough the heater A or externally adjacent there- I have illustrated inFigure 4 a conventional heater which does not include my baffle D. Herethe cold air downdraft generally follows the solid arrows 23'-flowingdownwardly into the heater A 'and out of the inlet 17 and alsoexternally adjacent the heater to set up the aforesaid cold drafts in. alooping counterflow with relation to the warm air flow 24. The latter isobviously inefficient as the cold air entering the grille 14 preventsescape of the warm air. I have observed that these grilles ofconventional heaters on cold days are warm only in spotty areas such asadjacent the opposite ends. In contrast, I have found that my grille isuniformly warm above orifice 19 throughout the length of the grille.

In Figure 5 I have illustrated a modified form of my invention which maybe employed to advantage especially in instances of a relatively widesill 15' adjacent-the window B. In this instance the falling cold aircurrents 23 are so horizontally or laterally spaced from the grille 14that these cold air currents do not have the aforesaid degree oftendency to travel downwardly through the stack 10. In such instances itis feasible to provide the curtain of accelerated rising curtain of warmair adjacent the inner rear wall 12 of stack 10. Thus in Fig. 5 mybaflle D is fixedly mounted to the inner front Wall 11 of stack 1th toprovide the orifice 19' between the rear edge of the baffle and wall 12for acceleration of rising warm air for mixing with the falling cold air23.

, In this instance the falling cold air is largely deflected upwardly atthe region of sill 15 but the same beneficial results as aforesaid inreference to Figs. 1 to 3 are obtained. The relatively wide or deep sill15' somewhat baflles the falling cold air so that it may be divertedupwardly by the rising warm air concentrated at the region above orifice19 adjacent the inner rear wall .12 of stack 10. Otherwise the resultingeffects in heating the room are identical with that aforesaid inreference to Figs. 1 to 3, it being understood that the lower end ofstack of Fig. 5 is the same as Fig. 2 including the heating element 18and inlet 17.

My invention is not to be confused with so-called volume controllingadjustable dampers hingedly mounted within the duct for regulating theflow of air therethrough. With such devices the damper is progressivelyopened in proportion to drop in ambient temperature and is fully openfor very cold weather conditions which induce the aforesaid colddowndrafts and permit them to set up the objectionable cold air draftsor currents in the room. With such prior devices cold downdrafts areinduced for flow into the room at greaterrand greater intensity asthe'ambient temperature becomes colder and colder. My baifle requires noadjustments as it is constantly operating to effect the aforesaiddeflection of the cold air downdraft regardless of variation in outsideair temperature and resulting variation in velocity of these downdrafts.Thus my baffle is preferably fixedly or permanently mounted in positionin the sense that it is not adapted for adjustment in its day to dayoperation to regulate the volume of warm air discharged from the duct inproportion to variations in ambient temperatures. The only variabledesirable to the maximum efficiency of my heater is the temperatureinduced in the heating element 18 which obviously should be maintainedat a higher degree as the ambient temperature decreases.

The structural details herein disclosed for the purpose of illustratingseveral forms of my invention may be widely varied without departingfrom the substance of the invention, or sacrificing the advantagesthereof, and hence I do not limit my invention to the specific structuredisclosed, except to the extent clearly indicated in specific claims,but reserve all such variations, modifications and equivalents as fallwithin the spirit and mm view of the claims.

I claim:

1. In a convection heater for use in a room adjacent a cold outsidewall, an upright. air stack having an air inlet opening into said roomadjacent the floor thereof and also having an air outlet openingupwardly into said roorn adjacent said wall at an upper portion of saidstack for vertical passage of heated air into said room, a heatingelement in said stack between said inlet and outlet for heating airentering said inlet, means to prevent downwardly flowing cold airadjacent said wall from entering said stack through said outlet andthence discharging from said inlet into said room comprising a baffleabove said heating element and underlying a substantial rear portion ofsaid outlet, said baffle extending from the rear of said stack towardthe front thereof to define a restricted orifice in said stack betweensaid heating element and outlet,

and means located above said heating element and closing the spacebetween said wall and the rear edge of said outlet and also closing thespace between said wall and the rear edge of said baifle proximate saidwall to block said downwardly flowing cold air from flowing into bothspaces, said bafile being arranged to direct upwardly flowing air insaid stack toward the front thereof through said orifice, the lattercooperating with said baffle to block cold air flowing downwardlyadjacent said wall from above said outlet and to effect reverse flow ofsaid cold air with the warm air flowing upwardly through said orifice.

2. In a convection heater for use in a room adjacent a cold outsidewall, an upright air stack having a forward surface spaced from saidwall, said stack having an air inlet opening forwardly into said roomadjacent the floor thereofto receive air from said room and also havingan air outlet opening upwardly into said room for vertical passage ofheated air thereinto, said outlet being adjacent said wall at an upperportion of said stack, a heating elementin said stack between said inletand outlet for heating air entering said inlet, means topreventdownwardly flowing cold air adjacent said wall from entering saidstack through said outlet and thence discharging from said inlet intosaid room comprising a baffle above said heating element and underlyinga substantial rear portion of said outlet, said baflle extendingforwardly from the rear of said stack and terminating at a forward edgeshort of said forward surface to define a restricted orifice in saidstack between said heating element and outlet,-

and means located above said heating element and closing the spacebetween said wall and the rear edge of said outlet and also closing thespace between said wall and the rear edge ofsaid baffle proximate saidwall to block said downwardly flowing cold air from flowing into bothspaces, said baffle being arranged to direct upwardly flowing air insaid stack toward said forward surface and through said orifice, thelatter cooperating with said baffle to block cold air flowing downwardlyadjacent said wall from above said outlet and to effect reverse flow ofsaid cold air with the warm air flowing upwardly through said orifice.

3. In a convection air heater for use in a room adjacent an outsidewall, a housing containing an upright air stack having a forward surfacespaced from said wall, said stack having an air inlet opening from saidroom adjacent the floor thereof and also having an air outlet adjacentsaid wall and opening upwardly into said room from an upper portion ofsaid stack for passage of heated air vertically through said outlet, aheating element in said stack between said inlet and outlet, saidhousing having a portion closing the space between said wall and theedge of said outlet proximate said wall to block the downward flow ofcold air adjacent said wall and into said space, and means to preventdownwardly flowing cold air adjacent said wall from entering said stackthrough said outlet and thence discharging from said inlet into saidroom comprising a baflle above said heating element and underlying asubstantial rear portion of said outlet, said baflie inclining from therear of said stack to a forward edge of said baffle spaced from saidforward surface to define a restricted orifice in said stack betweensaid heating element and outlet, said bafile being arranged to directupwardly flowing air in said stack toward said forward surface andthrough said orifice, the latter cooperating with said baflie to blockcold air flowing downwardly adjacent said wall from above said outletand to eifect reverse flow of said cold air with the warm air flowingupwardly through said orifice.

4. In a convection air heater for use in a room adjacent an outside walland below a window, a housing containing an upright air stack having aforward surface spaced from said wall, said stack having an air inletopening from said room adjacent the floor thereof, said housing having atop member adjacent the sill of said window and containingan air outletadjacent said wall and opening upwardly into said room from said stackfor passage of heated air vertically through said outlet, said topmember closing said stack except for said outlet and also closing thespace between said wall and the proximate edge of said outlet to blockdownwardly flowing cold air adjacent said window from flowing into saidspace, a heating element in said stack between said inlet and outlet,means to prevent said downwardly flowing cold air from entering saidstack through said outlet and thence discharging from said inlet intosaid room comprising a bafile above said heating element and underlyinga substantial rear portion of said outlet, said baffle incliningforwardly from the rear of said stack and terminating at a forward edgeshort of said forward surface to define a restricted orifice in saidstack between said heating element and outlet, said baffle beingarranged to direct upwardly flowing air in said stack toward saidforward surface and through said orifice, the latter cooperating withsaid baffle to block cold air flowing downwardly adjacent said wall fromabove said outlet and to effect reverse flow of said cold air with thewarm air flowing upwardly through said orifice, and a baflle portionconnecting said top member and the first-named batfle to close the spacebetween said first-named baflle and wall to block air flow into thelatter space.

References Cited in the file of this patent UNITED STATES PATENTS1,288,236 Shipp Dec. 17, 1918 1,608,938 Henshall Nov. 30, 1926 1,856,925Modine May 3, 1932 1,916,355 Bennett July 4, 1933 2,022,333 Woolley Nov.26, 1935 2,144,466 Stikeleather Jan. 17, 1939 2,345,537 Keep Mar. 28,1944 FOREIGN PATENTS 1,927 Australia May 2, 192 7

